Response Of Plant Leaf Traits To Microhabitats Change In An Subalpine Meadow Region On The Eastern Edge Of Qinghai-tibetan Plateau

The intrinsic physiological and external morphological of the plants vary with the changes of the environment.The adaptation measures are called plant traits,and which related to the leaves are called plant leaf traits.Belonged to one of the important characteristics of plants,Leaf traits have a direct effect on the function and basic behavior of plants,which can reflect the survival adaptation strategies of plants in order to obtain maximum carbon harvest and adapt to external changes.The slope aspect is one of the important topographic factors in the mountain.The change of the slope aspect affects the radiation that can be received on the surface,which leads to redistribution of ecological factors such as light,temperature,soil moisture and soil temperature.It can often create local microclimate.micro-habitat,which indirectly leads to the composition and distribution of plant species,and further affects the composition of biodiversity,ecosystem function,plant productivity and plant growth and development.Therefore,it is of great significance to study the relationship between plant leaf traits and micro-habitat.The species composition in the habitat gradient willshow a corresponding change due to the differences of light,temperature,water,soil and other factors of species.Understanding the changes of leaf traits and photosynthetic physiological characteristics of plants under micro-habitat can help us to explore the adaptation mechanism of species to habitat.It has very important practical significance for ecology and biological evolution.The response of plant leaf traits in five different slope aspects to microhabitat changes was studied on subalpine meadow in Gannan.And measure the species height,coverage,abundance,the leaf structural and functional properties of representative species were determined,and determination of plots of environmental factors.The results show:(1)South slope,Southwest slope,West slope,Northwest slope and North slope species were 10 families,21 genera,25 species and 14 families,31 genera,36 species and 17 families,35 genera,42 species and 22 families,41 genera,47 species and 18 families,42 genera,49 species.(2)Environmental factors in different slope were significantly different(p<0.05),In 2014 and 2015,the highest soil water content in half-shady slope(40.98%,37.92%);Sunny daylight illumination(105.51lx、92.97lx),daily soil temperature(23.56℃,25.57℃),soil pH(8.21 、 8.09)all is one of the biggest;soil nutrient content is the shady slope biggest and the west slope lowest for two consecutive years.(3)Specific leaf area,leaf dry matter,leaf water content,net photosynthetic rate,transpiration rate and water use efficiency were significantly different among the different slope aspects,indicating plant photosynthesis strategy was different in the different microhabitats.(4)Kobresiahumilis and Taraxacum mongolicum were dominant species in the sunny slope.Kobresia humilis,Taraxacum mongolicum,Gueldenstaedtia verna and Polygonum macrophyllum were dominant species in the half-sunny slope and west slope.Potentilla fruticosa,Polygonum macrophyllum and Stellera chamaejasme were dominant species in the half-shady slope and shady slope.(5)Habitat quality led to low biomass in the sunny slope and high biomass in the half-shady slope.Biodiversity and abundance were relatively low in the sunny slope and half-shady slope.Biomass was medium,and biodiversity and abundance were the highest in the west slope.The results showed that the soil moisture content,soil nitrogen content,soil phosphorus content,soil organic matter content,soil pH value,soil temperature in0~25cm deep,light intensity and other environmental factors varied with the change of slope direction,microclimate,the formation of micro-habitat.The structural and functional traits of plants were also vary with different aspect,reflecting the competition and adaptation mechanism of plants in microhabitat.Therefore,the study of the response of plant leaf traits to microbial changes,the selection of high light and high water use efficiency of the species can provide a scientific basis for the local vegetation restoration and the construction of sustainable ecosystem,which can help the protection of the typical species of the subalpine meadow community and the optimization of the artificial grassland.